Knobby exerciser



FIG. 1 is an isometric view of a knobby exerciser showing my new design;

FIG. 2 is an elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a sectional view taken along the plane 5-5 of FIG. 2; and,

FIG. 6 is a bottom isometric view thereof. 

CLAIM The ornamental design for a knobby exerciser, as shown. 